Island



(.No Model.)

, E. s. JONES. DEVICE FOR SECURING ZINC OR OTHER PRINTING PLATES. No.495,466. Patented Apr. 11, 1893.

UNITED STATES PATENT OFFICE.

EDWARD S. JONES, OF PROVIDENCE, RHODE ISLAND.

DEVICE FOR SECURING ZINC OR OTHER PRINTING PLATES.

SPECIFICATION forming part of Letters Patent No. 495,466, dated April11, 1893. I Application filed August 9, 1892. Serial No. 442,615. (Nomodel.) I

To all whom it may concern.-

Be it known that I, EDWARD S. J ONES, a citizen of the United States,residing at Providence, in the State of Rhode Island, have invented anew and useful Improvement in Devices for Securing Zinc or otherPrinting Plates, of which the following is a specification.

In placing lithographic zinc plates upon the bed of the press, there isa tendency in the metal to wrinkle, and to spring up in places from thesurface of the bed. This tendency of the zinc plate seriously interfereswith the operation of printing therefrom, and it is necessary in orderto obtain a the best results, that the plate should rest with its entiresurface upon the bed, and the object of my invention is to providesuitable means for securing the plate firmly and smoothly upon the bed,and it consists in the improved construction and arrangement of devices,as hereinafter fully set forth.

Figure 1, represents an end view, partly in section, of the bed anddevices for securing and straining the plate upon the same. Fig. 2,represents a partial side elevation, showing the back of the strainingdevice. Fig. 3, represents a back-view of the straining device separatefrom the bed, the nut for tightening the jaw upon the sheet of zinc,being removed. Fig. 4, represents a view of the clamping side of thetightening lever. Fig. 5, represents a section, taken in the line 5, 5,of Fig. l. Fig. 6, represents the face and edge view of the washer, heldunder the tightening nut. Fig. 7,isaback view of the straining-deviceshowing a modification. Fig. 8, represents a section of the same, takenin the line 8, 8, of Fig. 7.

In the accompanying drawings, A repre sents the bed of the printingpress, and B the zinc-plate by means of which the printing is to beperformed. Upon each side of the bed A, are placed the rods 0, C, whichmay be either made adjustable, or otherwise, as preferred, and uponwhich swing a series of tightening levers D, provided with the serratedclamping jaw E which may also be pivoted to the rod 0. The levers D areprovided with one or more recesses a, in each of which is placed aspiral spring I), having its outer end covered by a cap 0. The screwthreaded sleeve d, is firmly secured to the lever D, and is providedwith the internal screw thread 6, adapted to receive the thread of thetightening screw F, which is adapted to bear with its point against theside f of the bed A. The outer end of the sleeve 01 is provided with thescrew thread 9, upon which is placed the clamping nut G, which serves tooperate the clamping jaw E, and between the nut G and the clamping jaw,is placed the washer II, the said washer .being provided with a roundedinner face h, which bears against the recessed surface z' of theclamping jaw, the said jaw being provided with the shoulder j which bystriking against the side f of the bed, will serve to limit the outwardmovement of the said jaw when released from the printing plate.

, In operating the tightening device, the clamping nut G, is firstunscrewed upon the sleeve 01, thus allowing the clamping jaw E, to bethrown back from the tightening lever D, sufficiently, for the insertionof the edge of the plate B, between the said jaw and 1ever, after whichthe jaw E is to be brought firmly against the plate B, by screwing upthe nut G. Both sides of the supporting bed may have the samearrangement of devices, or one side may be provided with a permanent orstationary clamp, as may be desired. After the edge of the plate B hasbeen securely fastened as described, the tightening screw F is to beturned, which serves to force the top of the lever D, away from the sideof the bed A, thus straining the plate and bringing it closely incontact with the surface of said bed. The levers D being placed atintervals along the side of the bed A, and being capable of lateraladjustment upon the rod 0, allow the different portions of the plate tobe subjected to the degree of strain required to bring the entire plateto a perfectly smooth condition and in uniform contact with the surfaceof the bed.

A modification of my invention, is shown in Figs. 7 and 8, in which theclamping jaw E, is secured to the tightening lever D, by means of thescrews 1, l, which screw into the said lever, the intermediatetightening screw F, being arranged to bear against the side f of the bedA, as before, the spring I), also serving to throw back the jawE uponthe unscrewing of the clamping screws I, I.

I claim as my invention 1. The combination with the bed of the printingpress, of the tightening lever, pivoted upon a rod at the side of thebed, the tightening screw, adapted to operate the tightening lever, theclamping jaw pivoted to the rod, and means for operating the clampingjaw to clamp the plate, substantially as described.

2. The combination with the bed of the printing press, of the tighteninglever, pivoted upon a rod at the side of the bed, the tightening screw,adapted to operate the tightening lever, the clamping jaw pivoted to therod, means for operating the clamping jaw to clamp the plate, and thespring for causing the separation of the clamping jaw from the lever,upon unscrewing the clamping means, substantially as described.

3. The combination with the bed of the printing press, of the tighteninglever provided with the hollow sleeve, the tightening screw, theclamping jaw, and the clamping nut arranged upon the sleeve,substantially as described.

4. The combination with the bed of the printing press of the tighteninglever provided with the hollow sleeve, the tightening screw, theclamping jaw, the clamping nut arranged upon the sleeve, and the washerprovided with a rounded face adapted to bear against the side of theclamping jaw, substantially as described.

EDWARD S. JONES.

Witnesses:

SOORATES SCHOLFIELD, JAMES W. BEAMAN.

